The present invention is generally directed to encapsulated toner compositions, and imaging processes thereof. More specifically, the present invention is directed to encapsulated toners which contain fluorocarbon-incorporated core binders, including crosslinked core binders containing fluorocarbon segments, such as poly(fluoromethylene) blocks, and magnetic image character recognition imaging processes (MICR) thereof. In one embodiment, the encapsulated toners with the fluorocarbon-incorporated core binders can be selected for generating documents, such as personal checks, which can be subsequently processed in magnetic sensing reader/sorters. In an embodiment of the present invention, there are provided processes for generating documents, such as checks, including, for example, dividend checks, turn around documents such as invoice statements like those submitted to customers by American Express and VISA, corporate checks, highway tickets, rebate checks, identification badges, other documents with magnetic codes thereon, and the like, with desirable image magnetic signal strength, and no image smearing, or wherein image smearing is substantially minimized. More specifically, in one embodiment the process of the present invention is accomplished with certain encapsulated toner compositions wherein image smearing and offsetting to the read and write heads, including offsetting to the protective foil that may be present on the aforesaid heads in magnetic ink character recognition processes and apparatus inclusive of, for example, the read and write heads present in MICR (magnetic ink character recognition) reader/sorters, such as the commercially available IBM 3890.TM., NCR 6780.TM., reader/sorters from Burroughs Corporation, and the like, is minimized or avoided. Some of the reader/sorter printers contain protective foils thereon, reference for example the IBM 3890.TM., and the problems associated with such protective foils with respect to read and write heads with no foils are substantially alleviated with the processes of the present invention. With the processes utilizing the toner and developer compositions illustrated, the problems of image smearing to and offsetting from the read and write heads in magnetic ink character recognition apparatuses is substantially eliminated. Moreover, in another embodiment the present invention is directed to improved economical processes for generating documents, such as personal checks, suitable for magnetic image character recognition wherein image smearing and offsetting, including offsetting to read and/or write heads including those with protective foils thereon, or unprotected heads is avoided when such documents are processed in the aforementioned reader/sorters. Furthermore, in another embodiment of the present invention there is provided a MICR process wherein images of high resolution are obtained with an excellent image transfer efficiency of, for example, equal to or greater than 90 percent, and in embodiments from about 95 to about 99.9 percent.
Although it is not desired to be limited by theory, image offset is eliminated or minimized with the encapsulated toners and processes of the present invention, it is believed, primarily because of the presence of the low surface energy fluorocarbon moiety in the core binder structure. Offset results from, for example, some toner materials being removed from the developed image on the MICR (magnetic ink character recognition) document, such as a check, and transferred to the read and/or write heads contained in MICR readers/sorters, such as the IBM 3890.TM. and the NCR 6780.TM.. As a result, toner material is removed from the MICR images on the checks, or other documents primarily in a continuous manner causing image deformation and destruction of their magnetic integrity, which would lead to rejection in most instances during the reading and sorting process. The released toner materials from the MICR images as a result of the friction between the read/sort heads and the documents may also smear onto unprinted areas within the documents. With the encapsulated toners and processes of the present invention, these problems are avoided or minimized, and more specifically the reject rate is less than one half of 1 percent for 5,000 checks processed through, for example, in the aforesaid IBM 3890.TM. reader/sorter. When the aforesaid offset is eliminated or substantially reduced, the problem of image smearing onto the MICR documents, such as personal checks, is also avoided or minimized. With the processes and compositions of the present invention, in an embodiment thereof the reject rate is less than one half of 1 percent, it being noted that an acceptable reject rate usually does not exceed one half of 1 percent (0.5 percent) as determined by the American National Standards Institute (ANSI). Typically, the reject rate with the encapsulated toners and processes of the present invention is from about 0 to about 0.3 percent depending, for example, on the reader/sorter set up conditions as contrasted to a reject rate in excess of one half of 1 percent, which is usually not acceptable, with processes utilizing toner and developer compositions that contain, for example, no fluorocarbon-incorporated core binders.
With further respect to the present invention, the process is particularly applicable to the generation of documents including personal checks, which have been fused with pressure roll fusers. Pressure fixing systems, such as those incorporated in the commercial Xerox Corporation 4075.TM. and the Delphax S6000.TM. ionographic printers, are particularly useful with the processes of the present invention. In addition, fusing systems where heat is used, particularly in combination with pressure, for example where the above mentioned printers have been modified, are also applicable. Fuser rolls such as silicone rolls or other conformable fuser rolls, reference for example the soft fuser rolls incorporated into the Xerox Corporation 4040.TM. machine, are particularly useful with the toners, developers, and processes of the present invention. Fuser roll temperatures of, for example, about 80.degree. C. to about 165.degree. C. are suitable for the processes of the present invention in embodiments thereof.
The documents, including the personal checks mentioned herein, can be obtained, for example, by generating a latent image thereon and subsequently developing the image, reference U.S. Pat. No. 4,517,268, the disclosure of which is totally incorporated herein by reference, with the toner and developer compositions illustrated herein. The developed image that has been created, for example, in the Xerox Corporation 9700.TM. MICR printer, reference the aforesaid '268 patent, contains thereon, for example, the characters zero, 1, 2, 3, 4, 5, 6, 7, 8 and 9, and up to four symbols (E-13B and CMC-7 font), which characters are magnetically readable by the IBM 3890.TM., or other similar apparatus. One of the problems avoided with the processes of the present invention is to eliminate or reduce the offsetting of the toner as indicated herein to the read and write heads in the apparatus selected for this purpose, such as the IBM 3890.TM..
Processes for eliminating or minimizing image smearing in MICR processes are illustrated in U.S. Pat. No. 4,859,550, the disclosure of which is totally incorporated herein by reference. More specifically, there are illustrated in this patent processes for generating documents, which comprise the formation of images, such as latent images, with a printing device, especially devices generating from about 8 to about 135 prints per minute; developing the image with a single, or two component developer composition (toner plus carrier), which compositions contain, for example, resin particles, magnetite particles, low molecular weight hydrocarbons with functional groups, or polymeric alcohols; subsequently transferring the developed image to a suitable substrate; permanently affixing the image thereto; and thereafter processing the documents in reader/sorters wherein image offsetting and image smearing are avoided or substantially reduced. An example of the aforementioned process wherein a toner with no hydrocarbon, or polymeric alcohol additive is selected is illustrated in U.S. Pat. No. 4,517,268, the disclosure of which is totally incorporated herein by reference. Examples of high speed electronic printing devices disclosed in the aforementioned patent, which devices can also be utilized for the process of the present invention, include the 8700.TM. and 9700.TM. MICR printers available from Xerox Corporation. More specifically, there can be selected for the generation of the documents with magnetic characters thereon the Xerox Corporation 9700.TM. MICR printer, about 120 prints per minute, the Xerox Corporation 8700.TM. MICR printer, about 80 prints per minute, and the like. Some disadvantages associated with the polymeric alcohols and other additives of the aforementioned '550 patent, which disadvantages are avoided and/or minimized with the present invention, include objectionable odor during fusing, fuser roll contamination, and/or limited fuser roll life.
MICR processes with dry toner compositions comprised, for example, of resin particles, pigment particles, and external additives, such as fluorocarbons, such as TEFLON.RTM. and KYNAR.RTM., are illustrated in U.S. Pat. No. 5,034,298 (D/89067), the disclosure of which is totally incorporated herein by reference. More specifically, there is disclosed in the aforementioned patent processes for generating documents, which comprise the formation of images, such as latent images with a printing device, including devices generating from about 8 to about 135 prints per minute; developing the image with a single or two component developer composition (toner+carrier), which compositions contain, for example, resin particles, magnetite particles, and fluorocarbon components; subsequently transferring the developed image to a suitable substrate; permanently affixing the image thereto, and thereafter processing the documents in reader/sorters wherein image offsetting and image smearing are avoided or substantially reduced. According to the aforementioned patent, there can be selected for the generation of the documents with magnetic characters thereon the Xerox Corporation 9700.TM. MICR printer, about 120 prints per minute, the Xerox Corporation 8700.TM. MICR printer, about 80 prints per minute, and the like. Also, there can be selected for the processes with the toners and developers of the patent other devices including ionographic printers, such as the Delphax 4060.TM. printers, the Xerox Corporation 4040.TM., which contains a soft fuser roll for fixing purposes, the Xerox Corporation 4045.TM. and 4050.TM.. Thereafter, the formed documents with magnetic characters thereon can be processed in reader/sorter apparatuses and there results the advantages as indicated including low, and in some instances zero, reject rates. Examples of fluorocarbons disclosed in the patent include aliphatic and aromatic fluorocarbons, such as polyvinylidene fluoride, polytetrafluoroethylene, polyvinylfluoride, fully fluorinated polymeric ethylene propylene, polypentafluorostyrene, mixtures thereof, and the like, which fluorocarbons are present in various effective amounts. More specifically, the polymeric fluorocarbons are present, for example, in an amount of from about 0.1 percent to about 10 percent by weight. As internal additives, the polymeric fluorocarbons are preferably present in an amount of from about 2 percent by weight to about 10 percent by weight, while as external additives the fluorocarbons are preferably present in an amount of from about 0.3 percent by weight to about 2 percent by weight. Toner and developer compositions with the polymeric fluorocarbons present internally are formulated by initially blending the toner binder resin particles, pigment particles, and fluorocarbons, and other optional components. When the fluorocarbons are present as external additives, the toner composition is initially formulated comprised of, for example, resin particles and pigment particles; and subsequently there is added thereto the polymeric fluorocarbons. Usually, when present in the bulk of the toner or as an internal additive an effective amount of the polymeric fluorocarbon is exposed. The aforementioned fluorocarbons, which are commercially available from for example, Pennwalt Chemical Company, E. I. DuPont (TEFLON.RTM., KYNAR.RTM.), Liquid Nitrogen Products Corporation, and 3M.RTM., possess an average particle diameter of from about 0.1 to about 5, and preferably from about 0.2 to about 1 micron, it is believed. According to the copending application, of importance with respect to the processes thereof in an embodiment thereof is the presence of the aforementioned polymeric fluorocarbons with, for example, a molecular weight average of from less than about 10.sup.4 and preferably from about 10.sup.5 to about 10.sup.6, and a static coefficient of friction of from about 0.04 to about 0.3. It is believed that it is these components which, in combination with the other components of the toner and/or developer, eliminate, substantially reduce or minimize toner offsetting, including offsetting to the protective foil present on the read and write heads of reader/sorters present, for example, in the IBM 3890.TM. apparatus, and substantially eliminates or avoids image smearing as indicated herein.
In copending application U.S. Ser. No. 395,689 (D/89072), the disclosure of which is totally incorporated herein by reference, there are described encapsulated toners with fluorocarbon-incorporated resin binders, which binders and toners may be selected for the MICR processes of the present invention. In the aforementioned copending application, there are disclosed encapsulated toners useful for the development of xerographic images with a core containing colorants and a fluorocarbon-incorporated core resin binder, and a polymeric shell thereover. Specifically, in one embodiment there are disclosed in the copending application encapsulated toners comprised of a core containing a fluorocarbon-incorporated binder, that is wherein the fluorocarbon function is permanently attached to the core polymer binder by, for example, chemical processes, pigment or dye, and thereover a shell preferably obtained by interfacial polymerization. The aforementioned toners can be prepared by a number of different processes including the known chemical microencapsulation technique involving a shell forming interfacial polymerization and a core binder forming free radical polymerization processes; the said preparative process comprises (1) mixing or blending of a core monomer or monomers, a functionalized fluorocarbon compound, free radical initiator, pigment, and a shell monomer or monomers; (2) dispersing the resulting mixture of materials by high shear blending into stabilized microdroplets in an aqueous medium with the assistance of suitable surfactants or suspension agents; (3) thereafter subjecting the aforementioned stabilized microdroplets of a specific droplet size and size distribution to a shell forming interfacial polycondensation; and (4) subsequently forming the core binder by heat induced free radical polymerization within the newly formed microcapsules. The shell forming interfacial polycondensation is generally accomplished at ambient temperature, however, elevated temperatures may also be employed depending on the nature and functionality of the shell monomer selected. For the core binder forming free radical polymerization, heating thereof is generally effected at a temperature of from ambient temperature to about 100.degree. C., and preferably from ambient temperature to about 85.degree. C. In addition, more than one initiator may be utilized to enhance the polymerization conversion, and to generate the desired core copolymer binder molecular weight and molecular weight distribution. Examples of fluorocarbon reagents disclosed in the copending application include those as represented by the formula EQU A--(CF.sub.2).sub.x --B (I)
where A is a structural moiety containing an addition-polymerization functionality such as an acryloxy, methacryloxy, styryl, or other vinyl function capable of undergoing addition polymerization, preferably free radical polymerization; B is a fluorine atom or a structural moiety containing an addition-polymerization functionality as described herein for A; and x is the number of difluoromethylene groups of, for example, from 1 to about 50, and preferably from about 2 to about 20. Illustrative specific examples of functionalized fluorocarbon components, or reagents disclosed in the copending application that can be utilized in an effective amount, for example in one embodiment in an amount of from about 1 percent to about 20 percent by weight of the total core binder precursors used, include the commercially available acryloxy-functionalized fluorocarbon compounds and methacryloxy-functionalized fluorocarbon compounds represented by the following Formulas (II), (III), (IV) and (V) wherein R is hydrogen or alkyl; R' is alkylene, arylene, or the derivatives thereof; and x represents the number of difluoromethylene segments, for example, x can be a number from about 1 to about 50, and preferably from about 2 to about 20: ##STR1##
Illustrated in a U.S. Pat. No. 4,758,506, the disclosure of which is totally incorporated herein by reference, are single component cold pressure fixable toner compositions, wherein the shell selected can be prepared by an interfacial polymerization process. A similar teaching is present in abandoned patent application U.S. Ser. No. 718,676, the disclosure of which is totally incorporated herein by reference. In the aforementioned application, the core can be comprised of magnetite and a polyisobutylene of a specific molecular weight encapsulated in a polymeric shell material generated by an interfacial polymerization process.
Encapsulated and cold pressure fixable toner compositions are known. Cold pressure fixable toners have a number of advantages in comparison to toners that are fused by heat, primarily relating to the utilization of less energy since the toner compositions used can be fixed at room temperature. Cold pressure fixability also enables the machine's instant-on feature and permits the design of compact size high speed printers for space saving considerations. Nevertheless, many of the prior art cold pressure fixable toner compositions suffer from a number of deficiencies. For example, these toner compositions must usually be fixed under high pressure, which has a tendency to severely disrupt the toner's fixing characteristics. This can result in images of low resolution. The high fixing pressure can also lead to objectionable paper calendering and glossy images. With some of the prior art cold pressure toner compositions, substantial image smearing can result from the high pressures used. Additionally, a number of the cold pressure fixing toner compositions of the prior art have other disadvantages in that, for example, these compositions generate images of inferior crease and rub resistance properties, and the said images can often be readily rubbed off with pressure or removed by folding. Also, undesirable core component leaching results with a number of the prior art cold pressure fixable toner compositions, a disadvantage eliminated, or minimized with the processes and toners of the present invention.
The following prior art, all United States patents, is mentioned and was located as a result of a patentability search report for related copending application U.S. Ser. No. 395,689 (D/89072) mentioned herein: U.S. Pat. No. 4,339,518, which relates to a process of electrostatic printing with fluorinated polymer toner additives where suitable materials for the dielectric toner are thermoplastic silicone resins and fluorine containing resins having low surface energy, reference column 4, beginning at line 10, note for example the disclosure in column 4, line 16, through column 6; U.S. Pat. No. 4,016,099, which discloses methods of forming encapsulated toner particles and wherein there are selected organic polymers including homopolymers and copolymers such as vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene, and the like, see column 6, beginning at line 3, wherein there can be selected as the core materials polyolefins, polytetrafluoroethylene, polyethylene oxide and the like, see column 3, beginning at around line 18; U.S. Pat. No. 4,265,994 directed to pressure fixable capsule toners with polyolefins, such as polytetrafluoroethylene, see for example column 3, beginning at line 15; U.S. Pat. No. 4,497,885, which discloses a pressure fixable microcapsule toner comprising a pressure fixable component, a magnetic material, and other optional components, and wherein the core material can contain a soft material typical examples of which include polyvinylidene fluoride, polybutadiene, and the like, see column 3, beginning at line 10; U.S. Pat. No. 4,520,091 discloses an encapsulated toner with a core which comprises a colorant, a dissolving solvent, a nondissolving liquid and a polymer, and may include additives such as fluorine containing resin, see column 10, beginning at line 27; U.S. Pat. No. 4,590,142 relating to capsule toners wherein additives such as polytetrafluoroethylenes are selected as lubricating components, see column 5, beginning at line 52; U.S. Pat. No. 4,599,289 and U.S. Pat. No. 4,803,144.
With further reference to the prior art, there are disclosed in U.S. Pat. No. 4,307,169 microcapsular electrostatic marking particles containing a pressure fixable core, and an encapsulating substance comprised of a pressure rupturable shell, wherein the shell is formed by an interfacial polymerization. One shell prepared in accordance with the teachings of this patent is a polyamide obtained by interfacial polymerization. Furthermore, there is disclosed in U.S. Pat. No. 4,407,922 pressure sensitive toner compositions comprised of a blend of two immiscible polymers selected from the group consisting of certain polymers as a hard component, and polyoctyldecylvinylether-co-maleic anhydride as a soft component. Interfacial polymerization processes are also selected for the preparation of the toners of this patent.
In a patentability search report for copending application U.S. Pat. No. 5,034,298 (D/89067), there was recited the following prior art, all United States patents: U.S. Pat. No. 4,517,268, the disclosure of which is totally incorporated herein by reference, which illustrates xerography to print MICR legends, and more specifically describes a MICR process wherein the developer is comprised of a toner of magnetite and resin, and the carrier is comprised of ferrite cores; also note column 3, beginning at around line 15, wherein it is indicated that the process of the '268 patent in one embodiment involves the generation of documents including personal checks, which documents are suitable for magnetic image character recognition and wherein conventional electrostatographic methods are selected, and wherein the magnetic toner composition contains from about 20 percent by weight to about 70 percent by weight of various magnetites and 30 to 80 percent of certain toner resin particles; and also note the disclosure in column 5, beginning at line 10, wherein developer compositions are formulated; U.S. Pat. No. 4,268,598, the disclosure of which is totally incorporated herein by reference, which discloses a developer comprised of toner powder particles and a fluoroaliphatic sulfonamido surface active material, which developers may be selected for printing tickets, and the like, reference column 10 for example; also note column 7, wherein both pressure fixable and heat fusible toners may be employed, preferably conductive and magnetically attractable; U.S. Pat. No. 4,339,518, the disclosure of which is totally incorporated herein by reference, which discloses the incorporation of fluorine containing resins in a toner that will form a xerographic print that can be selected as a printing master; also note column 4, beginning at around line 16, wherein the dielectric toner contains a particular flow reading containing resin in an amount of at least 0.5 percent by weight calculated as fluorine, and that the fluorine containing resin has an excellent frictional charging property, a low surface energy, and excellent lubricating property with examples of the fluorine containing resins being outlined in column 4, beginning at around line 40, and the preparation of dielectric toner wherein the fluorine is incorporated into the toner composition is outlined in column 6, beginning at line 26; U.S. Pat. No. 4,388,396, the disclosure of which is totally incorporated herein by reference, which discloses magnetic toners with incorporated fluorocarbons as offset preventing agents; also disclosed, reference column 3, are developers including one component type developer comprising particles in which a fine powder of a magnetic substance has been incorporated therein with examples of aliphatic fluorocarbons being illustrated in column 4, beginning at around line 18, and examples of magnetites being outlined in column 9, beginning at around line 36; further, note that the fluorocarbon is incorporated into the toner, and note the disclosure beginning in column 10, line 25; U.S. Pat. No. 4,560,635 relating to magnetic toners wherein, for example, vinylidene fluoride can be selected as a resin; U.S. Pat. No. 4,590,142 relating to the use of polytetrafluoroethylene as a lubricant for magnetic toners; and as background or collateral interest U.S. Pat. No. 3,778,262; U.S. Pat. No. 3,977,871; U.S. Pat. No. 4,002,570 and U.S. Pat. No. 4,051,077.
Described in U.S. Pat. No. 4,367,275 are methods of preventing offsetting of electrostatic images of the toner composition to the fuser roll, which toner subsequently offsets to supporting substrates such as papers, wherein there are selected toner compositions containing specific external lubricants including various waxes, see column 5, lines 32 to 45, which waxes are substantially different in their properties and characteristics than the additives selected for the toner and developer compositions of the present invention; and moreover, the toner compositions of the present invention with the aforementioned fluorocarbon additives possess advantages, such as elimination of toner spotting, not achievable with the toner and developer compositions of the '275 patent.